Advances in Emerging Electronic Nanomaterials: Synthesis, Enhanced Properties, Integration, and Applications: Graphene and Other Nanomaterials
Sponsored by: TMS: Nanomaterials Committee
Program Organizers: Chang-Yong Nam, Brookhaven National Laboratory; Jung-Kun Lee, University of Pittsburgh; Stephen McDonnell, University of Virginia
Monday 2:00 PM
October 10, 2022
Room: 321
Location: David L. Lawrence Convention Center
Session Chair: Chang-Yong Nam, Brookhaven National Laboratory; Jung-Kun Lee, University of Pittsburgh
2:00 PM Invited
Novel Dirac-source Cold Carrier Injection for Energy-efficient 2D Nanoelectronics: Huamin Li1; Fei Yao1; 1University at Buffalo
Room-temperature Fermi-Dirac electron thermal excitation in conventional three-dimensional (3D) or two-dimensional (2D) semiconductors generates hot electrons with a relatively long thermal tail in energy distribution. Here, we investigated graphene (Gr)-enabled cold electron injection where the Gr acts as the Dirac source to provide the cold electrons with a localized electron density distribution and a short thermal tail at room temperature. These cold electrons correspond to an electronic refrigeration effect in monolayer MoS2 and WSe2, which enables a transport factor lowering and thus a steep-slope switching mechanism for MoS2 and WSe2 field-effect transistors (FETs). Especially, a record high sub-60-mV/decade current density (over 1 μA/μm) can be achieved compared to conventional steep-slope technologies such as tunneling FETs or negative capacitance FETs using 2D or 3D channel materials. Our work demonstrates the potential of a 2D Dirac-source cold electron transistor as a steep-slope transistor concept for future energy-efficient nanoelectronics.
2:30 PM Invited
How to Achieve State-of-the-art Heterostructures from Polymer-contaminated Graphene?: Zhujun Huang1; Suji Park2; Kevin Yager2; Davood Shahrjerdi1; 1New York University; 2Brookhaven National Laboratory
Various materials techniques (e.g., chemical vapor deposition) can now produce macroscopic scale graphene. Despite these advances, constructing similarly sized van der Waals (vdW) heterostructures with atomically clean interfaces is still unrealized. A primary reason is the contamination of graphene with polymers during preparation and film handling. The general belief is that clean heterostructures cannot be made using polymer-contaminated graphene.Contrary to this belief, we show the complete removal of polymer residues from vdW interfaces across the entire dimension of graphene heterostructures. We do so by introducing a simplified picture of interface cleaning that hypothesizes the physical processes occurring at the vdW interfaces. We validate those hypotheses through extensive experiments performed using Quantum Materials Press (QPress) tool, a unique and high precision layered assembly setup developed at Brookhaven National Laboratory. Our study paves the way for fabricating clean heterostructures with a state-of-the-art electronic performance from polymer-contaminated graphene.
3:00 PM Invited
Nanomaterials for Energy-efficient Memory Devices: Jung-Kun Lee1; 1University of Pittsburgh
The presentation will show new materials design for energy-efficient memory devices. One emerging application of the halide perovskite is the resistive random-access memory (ReRAM) as a promising next-generation nonvolatile memory device. Recently, we reported the asymmetric resistive switching of the halide perovskite film. Schottky barrier induced by TiO2 interfacial layer exhibits lower current at high resistive switching state and larger space charge polarization, which could be useful to ReRAM application. The other material of interest for memory devices is layered compounds of Aurivillius phase, Bi5FeTi3O15. Regardless of multiferroic property and high Curie temperature, it has several inherent problems such as high leakage current, small polarization, and large coercive field. Our recent comprehensive analysis shows how to resolve this problem. Cr doping significantly changes the electric, dielectric, and ferroelectric properties of Bi5FeTi3O15 by reducing the lattice aspect ratio and changing the grain shape.
3:30 PM
Solution Processible Carbon Precursors for 2D Amorphous Carbon Dielectric: Congjun Wang1; Viet Hung Pham1; Fufei An2; Christopher Matranga1; Qing Cao2; 1National Energy Technology Laboratory; 2University of Illinois at Urbana-Champaign
Two-dimensional (2D) semiconductors and semimetals could enable performance and scaling of solid-state electronic devices beyond the limits of those built on their conventional bulk counterparts. However, their suitable accompanying 2D dielectric, ideally in the highly disordered amorphous form similar to SiO2 for silicon, has not been identified, which prevents nanoelectronic devices based on low-dimensional nanomaterials from fulfilling their potential. The synthesis of 2D amorphous dielectrics and their integration into electronic devices are challenging due to the metastable nature of amorphous phases. Here we discuss the synthesis of a solution processible precursor to enable a scalable and solution-based strategy to prepare large-area and freestanding 2D amorphous carbon monolayers and multilayers as novel dielectrics. The synthesis and characterization of the carbon precursor and the 2D amorphous carbon film will be described. To demonstrate the effectiveness of the 2D amorphous carbon as dielectric materials, carbon nanoelectronic devices are fabricated and evaluated.
3:50 PM Break
4:05 PM
Correlative Analyses of Low-dimensional Materials: Veronika Hegrova1; Radek Dao1; Jan Neuman1; 1NenoVision s.r.o.
Correlative microscopy, in general, combines different imaging systems and their benefits to understanding the material principles. It has become an essential tool helping us understand the complexity of the sample properties. When we imagine the setup of two complementary techniques, atomic force microscopy (AFM) and scanning electron microscopy (SEM), it has several advantages, such as multimodal measurement, under in-situ conditions and precise localization to the area of interest.In low-dimensional materials, lots of time is spent searching the area of interest due to their small size. Correlative Probe and Electron Microscopy (CPEM) is a unique method allowing for precise AFM and SEM data correlation. The images are acquired simultaneously from both devices in the same coordinate system enabling the connection of mechanical, electrical, and material properties. Thus, resulting 3D CPEM views can combine multiple channels from AFM and SEM, enabling thorough sample analysis and clear data interpretation.
4:25 PM
Nanomolding of Topological Nanowires: Mehrdad Kiani1; Hyeuk Jin Han1; Quynh Sam2; Judy Cha1; 1Yale University; 2Cornell University
Due to their symmetry-protected states, topological nanostructures possess electronic properties that make them potentially transformative for a wide variety of fields. Theoretical calculations predict that 27% of crystalline structures have topological states; however, experimental studies have only focused on several model systems. Currently, the bottleneck for widespread study and use of topological nanostructures is synthesis. Here, we introduce the use of thermomechanical nanomolding, whereby a bulk feedstock is pressed at an elevated temperature through a mold with nanoscale 1D pores, for the fabrication of topological nanowires. MoP and CoSn, both Dirac semimetals, are fabricated via nanomolding with varying diameters. TEM analysis of fabricated nanowires showed they are single crystal with high aspect ratios. As both MoP and CoSn are potential replacements for Cu as interconnect materials, we performed four-point probe resistivity measurements for various diameter nanowires and compare the values to nanowires grown using other techniques, such as CVD.
4:45 PM
Unique Molecular Approach to 2D Tin Chalcogenide Materials by Single-Source Precursor Design: Fabian Hartl1; Veronika Brune1; Sanjay Mathur1; 1University of Cologne
Tin-based selenides (SnSe and SnSe2) have been explored to be the next generation of flexible materials for electronic, optical, and optoelectronic applications. By introducing a chelating tridentate coordinating (-SeEtN(Me)EtSe-) ligand system to tin(IV) chloride, air stable and monomeric complexes have been obtained. Variation of the synthetic procedure in similar synthetic routes enabled the isolation of two different tin(IV) complexes [Sn(SeEtN(Me)EtSe)2] and [SnCl2(SeEtN(Me)EtSe)] which have been characterized by NMR measurements and single crystal XRD. The homoleptic tin compound offers the temperature depending material preparation for both SnSe and SnSe2. This has been investigated by detailed thermal decomposition methods and identified by XRD measurements to confirm the phase pure SnSe and SnSe2 formation. [Sn(SeEtN(Me)EtSe)Cl2] offers the possibility to synthesize the heteroleptic complex [Sn(SeN(Me)EtSe)(SEtN(Me)EtS)] to target the synthesis of the ternary SnSSe. This heteroleptic tin(IV) complexe has been investigated by detailed NMR studies as well as by single crystal XRD.
5:05 PM
Near-Band-Edge Enhancement in Perovskite Solar Cells via Tunable Surface Plasmons: Yulin Liu1; 1University of Pittsburgh
We designed plasmonic perovskite solar cells (PSCs) using core-shell type plasmonic particles, which possess the plasmon resonance in the near-infrared range. This can selectively strengthen the interaction of the perovskite layer with low-energy photons. The mesoporous PSCs employing the plasmonic particles have delivered a 15-20% enhancement of external quantum efficiency in the plasmonic resonance range. This surface-plasmonic effect has been analyzed using complementary techniques, including selective wavelength excitation and time-dependent photoluminescence. It is shown that the metal-based core-shell-type plasmonic structures in PSCs optimize the scattering and absorption of incident light and the dynamics of photogenerated carriers. Furthermore, both optical and electronic effects increase the power conversion efficiency of PSCs from 17.49 % to 19.88 %, paving a way toward controlling the thickness of the photoactive layer for advanced devices such as tandem solar cells.
5:25 PM
Hybrid Liquid Metal Nanostructures for Electronics and Energy Applications: Weinan Xu1; 1University of Akron
Liquid metal (LM) is an emerging class of material that holds great potential in soft electronics, energy storage, and biomedicine due to its unique combination of conductivity, self-healing, and fluidity at room temperature. But the fluid nature also presents significant challenges in their processing, patterning, and integration with other materials. One effective way to address this issue is to disperse LM into nanoparticles. However, LM NPs are not stable in aqueous suspension and prone to aggregation and oxidation. Therefore, there is a strong need to create hybrid LM nanostructures with enhanced stability, processability, and new functionalities. In this talk, I will present our recent progress in core-shell hybrid nanocolloids with LM core and functional polymer shells. The polymer shell can also be carbonized to create LM nanoparticles with conductive carbon shell. Furthermore, the hybrid nanocolloids can be assembled, patterned, and used for electronic and energy devices with enhanced performance.
5:45 PM
Stable Perovskite Solar Cells: Seongha Lee1; 1University of Pittsburgh
Photovoltaics (PVs), which convert solar energy into electricity, is one of the promising energy devices which can decrease a dependance on fossil energy. Recently, organo-lead-halide perovskite, CH3NH3PbX3 (X=I, Cl, Br) has attracted a huge amount of interest due to its excellent light absorption and carrier transport for the perovskite solar cells (PSCs). Despite these advantages, commercialization of PSCs is still challenging due to poor stability when exposed to humid.Here, we present a simple and effective passivation method to elongate the lifetime of the PSC devices. Interpenetrating polymer networks (IPNs) with PMMA and PU showed better passivation behavior than individual polymer. In addition, the combination of oxide nanoparticles with the IPNs make a twisted path for the permeating water molecule and changed their physical properties. As a result, the encapsulated devices exhibit dramatically suppressed degradation process in a standardized damp heat aging condition (85/85 ℃/RH condition).